The present invention relates to a semiconductor device. For example, the invention is preferably used for a semiconductor device including a nitride semiconductor.
A semiconductor device including a III-V compound having a bandgap larger than that of silicon (Si) are now the subject of interest. In particular, a MISFET including gallium nitride (GaN) is advantageous in 1) a high dielectric breakdown field, 2) a high electron saturation velocity, 3) a large thermal conductivity, 4) formation of a good heterojunction between AlGaN and GaN, and 5) a nontoxic or safe material.
For example, Japanese Unexamined Patent Application Publication No. 2010-109086 discloses a normally-off nitride semiconductor element, in which a p-GaN layer is electrically coupled to a source electrode via a contact plug.